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Changes of Chlorophyll(ide) Fluorescence Yield Induced by a Short Light Pulse as a Probe to Monitor the Early Steps of Etioplast Phototransformation in Dark‐Grown Leaves
Author(s) -
Eullaffroy Philippe,
Popovic Radovan,
Franck Fabrice
Publication year - 1998
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1998.tb09112.x
Subject(s) - protochlorophyllide , fluorescence , quantum yield , photochemistry , yield (engineering) , chemistry , chlorophyll fluorescence , photosynthesis , chlorophyll , kinetics , biophysics , analytical chemistry (journal) , biology , biochemistry , chloroplast , optics , materials science , chromatography , physics , organic chemistry , metallurgy , quantum mechanics , gene
ABSTRACT The fluorescence yield of chlorophyll(ide) (Chl[ide]) excited by weak modulated light was recorded at room temperature during a 2 h period after a short actinic light pulse that transformed all photoactive protochlorophyllide in dark‐grown barley leaves. A typical pattern of fluorescence yield variations was found whatever the age of the leaf but with age‐dependent changes in rates. Its successive phases were related to the Chl(ide) spectral shifts observed in low‐temperature emission spectra. The fluorescence yield started at a high level and strongly declined during the formation of Chlide 695 from Chlide 668 within a few seconds. It increased to a transient maximum during the Shibata shift (15–25 min) that resulted in Chl(ide) 682 . A final, slow decrease to a steady state occurred during the final red shift to Chl 685 . Pretreatments with δ‐aminolevulinic acid, chloramphenicol or 1, 10‐phenanthroline resulted in correlated modifications of Chl(ide) fluorescence yield transients and shifts of the low‐temperature Chl(ide) emission band. The complex response of the final decrease phase of the fluorescence yield to these compounds suggests that it results both from the assembly of photosynthetic Chl proteins and from the reorganization of the etioplast membrane system. From these results it is concluded that continuous recordings of Chl(ide) fluorescence yield after a short light pulse represent a useful tool to monitor the kinetics of pigment–protein organization and primary thylakoid assembly triggered by Pchlide photoreduction.